Electrode lead wire member and battery

ABSTRACT

Provided are an electrode lead wire member including a sealing film having high adhesive strength and resistance to an electrolytic solution, and a battery including the electrode lead wire member. Provided is an electrode lead wire member including: a derivation portion extending in one direction; a surface-treated layer formed, at the derivation portion, on a surface of the derivation portion; and a sealing film provided in contact with the surface-treated layer, in which the sealing film has an adhesive resin layer in contact with the surface-treated layer, and the adhesive resin layer contains imine-modified polyolefin or modified polyolefin having a carbodiimide group.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the priority from Japanese Patent ApplicationNo. 2018-018521 (filing date: Feb. 5, 2018). The entire teachings of theabove application are incorporated herein by reference.

BACKGROUND OF THE INVENTION (1) Field of the Invention

The present invention relates to an electrode lead wire member and abattery.

(2) Description of Related Art

In recent years, a secondary battery, a capacitor, and the like,packaged in a container including a film, have been adopted as a powersource of electronic equipment such as a laptop computer and a cellularphone, a battery for an automobile such as a hybrid vehicle, a fuelbattery automobile, and an electric automobile.

The above-mentioned automobiles are small in load on the environment ascompared with a gasoline automobile, and each automobile manufacturer isputting effort into development of the above-mentioned automobiles. Inthose automobiles, since electric power that is charged and dischargedis large, a battery has also been enlarged.

Conventionally, these secondary batteries and capacitors have beenconfigured by enclosing power generation elements into a flat container.In this container, an electrode lead wire member for charge anddischarge is sealed with one end thereof protruding outward. Uponsealing, a tape-like electrode lead wire member is held between filmsubstrates of the container, and the film substrates are heat-sealed.

Examples of these film substrates include a film-like laminate in whichsubstrate layer/adhesive layer/metal layer/sealant layer are laminatedsequentially. For example, Japanese Unexamined Patent Application, FirstPublication No. 2017-120790 describes an adhesive film for sealing anelectric storage device metal terminal part comprising a heat-resistantsubstrate layer and an insulating layer. Japanese Unexamined PatentApplication, First Publication No. 2017-120790 describes that theinsulating layer is formed using a composition for an insulating layercomprising acid-modified polyolefin and a curing agent.

SUMMARY OF THE INVENTION

A sealing film used in a sealing material for a secondary battery or acapacitor is required to be improved in adhesive strength for realizinghigh sealing strength, and additionally is required to have resistanceto an electrolytic solution supposing that the film comes in contactwith the electrolytic solution.

The present invention has been made in view of the above-mentionedcircumstances, and an object thereof is to provide an electrode leadwire member comprising a sealing film having high adhesive strength andresistance to an electrolytic solution, and a battery comprising theelectrode lead wire member.

That is, the present invention has adopted the following constituentfeatures.

[1] An electrode lead wire member comprising: a derivation portionextending in one direction; a surface-treated layer formed, at thederivation portion, on a surface of the derivation portion; and asealing film provided in contact with the surface-treated layer, whereinthe sealing film has an adhesive resin layer in contact with thesurface-treated layer, and the adhesive resin layer containsimine-modified polyolefin or modified polyolefin having a carbodiimidegroup.[2] The electrode lead wire member according to [1], wherein thesurface-treated layer has an acidic group.[3] The electrode lead wire member according to [1] or [2], wherein thesealing film only includes the adhesive resin layer.[4] The electrode lead wire member according to [1] or [2], wherein inthe sealing film, the adhesive resin layer, a substrate layer, and asecond adhesive resin layer are laminated in that order.[5] The electrode lead wire member according to [4], wherein a resinconstituting the substrate layer is one or more selected from the groupconsisting of a fluorine resin, polyether ether ketone, a polyphenylenesulfide resin, polyphenylene ether, a syndiotactic polystyrene resin,polyethylene naphthalate, polyethylene terephthalate, a polyimide resin,a phenol resin, an epoxy resin, an acrylic resin, polyketone, a cyclicolefin resin, polymethylpentene, polypropylene, and polyethylene.[6] The electrode lead wire member according to any one of [1] to [5],comprising one pair of the sealing films holding the derivation portion,wherein in the one pair of the sealing films, the adhesive resin layersface and come in contact with each other, and simultaneously come incontact with a whole circumference in a circumferential direction of thederivation portion to cover the derivation portion.[7] A battery comprising the electrode lead wire member with the sealingfilm according to any one of [1] to [6].

According to the present invention, there can be provided an electrodelead wire member comprising a sealing film having high adhesive strengthand resistance to an electrolytic solution, and a battery comprising theelectrode lead wire member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a state where an electrode leadwire member of the present invention and a laminate for a battery outerpackage are joined;

FIG. 2 is a cross-sectional view showing a state where the electrodelead wire member of the present invention and the laminate for a batteryouter package are joined;

FIG. 3 is a perspective view showing one example of the electrode leadwire member of the present invention;

FIG. 4 is a perspective view showing one example of a battery; and

FIGS. 5A to 5C are views for illustrating a surface-treated portion ofthe electrode lead wire member.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, a preferred embodiment of the present invention will bedescribed.

Note that the following embodiment is one example of the presentinvention, and the present invention is not limited to this.

<Electrode Lead Wire Member and Battery>

The electrode lead wire member of the present invention will bedescribed while a configuration of a battery of the present embodimentis described.

First, the electrode lead wire member of the present embodimentcomprises a derivation portion extending in one direction, asurface-treated layer formed, at the derivation portion, on a surface ofthe derivation portion, and a sealing film provided in contact with thesurface-treated layer.

It is preferable that the surface-treated layer has an acidic group. Thesealing film has an adhesive resin layer in contact with thesurface-treated layer. The adhesive resin layer contains imine-modifiedpolyolefin or modified polyolefin having a carbodiimide group.

FIG. 4 shows one example of a battery 20 a of the present embodiment. Inthe battery 20 a, an electrode lead wire member 10 of the presentinvention and a lithium ion battery 17 are included in a batteryexterior container that is prepared by folding a laminate 20 for abattery outer package.

Furthermore, each of three side edges 19 of the battery 20 a is formedby heat-sealing the laminate 20 for a battery outer package to make thelaminate 20 into a bag. The electrode lead wire member 10 is pulled outfrom the battery 20 a, as shown in FIG. 4.

FIG. 1 shows a cross-sectional view along X-X line of FIG. 4.

The electrode lead wire member 10 comprises a derivation portion 11having a surface-treated layer 2 on each of both surfaces, and a sealingfilm 1 that is laminated so as to come in contact with a surface of thesurface-treated layer 2. In an aspect shown in FIG. 1, the sealing film1 is a monolayer film only including an adhesive resin layer.

Furthermore, the electrode lead wire member 10 is fused with thelaminate 20 for a battery outer package via the sealing film 1 includedin the electrode lead wire member 10.

The laminate 20 for a battery outer package comprises a film substratelayer 23, a metal foil layer 21, and a sealant layer 22.

FIG. 2 shows a cross-sectional view along a longitudinal direction ofthe electrode lead wire member 10 in another aspect of the presentinvention. In this aspect, a sealing film 33 may be a laminate in whichan adhesive resin layer 30, a substrate layer 31, and a second adhesiveresin layer 32 are laminated in that order.

FIG. 3 is a perspective view showing one example of the electrode leadwire member 10 of the present embodiment.

The electrode lead wire member 10 has one pair of the sealing films 1holding the derivation portion 11.

In the one pair of the sealing films 1, the adhesive resin layers faceand come in contact with each other, and simultaneously come in contactwith a whole circumference in a circumferential direction of thederivation portion 11 to cover the derivation portion.

In the electrode lead wire member shown in FIG. 3, the surface of theelectrode lead wire member has been subjected to surface treatment shownwith reference numeral 2 in a belt manner.

As the surface treatment of the electrode lead wire member, an uppersurface of the lead wire member and a bottom surface (not shown) on anopposite surface of the upper surface can also be treated as shown inFIG. 5A. Reference numeral 100 in FIG. 5A means a surface that has beensubjected to surface treatment. Reference numeral 101 in FIG. 5A means asurface that has not been subjected to surface treatment.

In the case of the configuration as in FIG. 5A, the member can beproduced by cutting a metal foil having a great area in which an uppersurface and a rear surface thereof have been subjected to surfacetreatment. For that reason, this is preferable from the viewpoint ofimproving the production efficiency and the mass production suitability.

A whole surface of the lead wire member can also be treated, as shown inFIG. 5B. Reference numeral 100 in FIG. 5B means a surface that has beensubjected to surface treatment.

In the case of the configuration as in FIG. 5B, since a whole surface ofa metal foil that has been cut in a whole surface can be subjected tosurface treatment at once, uniform surface treatment can be performed.

As shown in FIG. 5C, treatment may be performed in a range shown withreference numeral 100 in the circumferential direction of the electrodelead wire member, and an end portion may be a surface that has not beensubjected to surface treatment as shown with reference numeral 101.

In the case of the configuration as in FIG. 5C, the member can beproduced by cutting a long bar-like metal foil having a surface that hasbeen subjected to surface treatment. For that reason, this is preferablefrom the viewpoint of improving the mass production suitability.

The electrode lead wire member of the present embodiment comprises asurface-treated layer 2 in which an acidic group is exposed on a surfaceof the derivation portion 11. The acidic group included in thesurface-treated layer 2 and imine-modified polyolefin or modifiedpolyolefin having a carbodiimide group in the adhesive resin layer arereacted to bond firmly. Accordingly, the adhesive layer firmly adheresto an adherend, and additionally, the strength of the electrode leadwire member with a sealing film can be secured. As a result, theelectrode lead wire member of the present embodiment has resistance toan electrolytic solution, in addition to high adhesive force.

<<Derivation Portion>>

As a material of the derivation portion 11, for example, known metalsuch as aluminum, copper, nickel, iron, gold, platinum, and variousalloys can be used. Among them, aluminum and copper are preferably useddue to excellent electrical conductivity and an advantage in cost.However, aluminum and copper may not be sufficient in resistance tohydrogen fluoride (hydrofluoric acid) that may have the risk of beinggenerated in an electrolytic solution in a battery pack.

When the derivation portion 11 is plated with nickel, electroplating maybe performed using a Watts bath containing nickel sulfate, nickelchloride, boric acid, and the like as main components, but when a nickelsulfamate plating bath containing nickel sulfamate and boric acid asmain components is used, a plating film to be formed has low stress andis excellent in flexibility, so that this is preferable. When excellentin flexibility, the plating film has few defects such as cracking. It isparticularly preferable that the derivation portion is an aluminum andnickel-plated copper plate.

<<Surface-Treated Layer>>

The surface-treated layer 2 is formed on the surface of the derivationportion 11. It is preferable that an acidic group is exposed on asurface of the surface-treated layer 2.

Examples of a method of exposing an acidic group on the surface-treatedlayer 2 include a method of performing chromate treatment, a method ofperforming chitosan treatment, and a method of performing treatment witha carboxylic acid-modified water-soluble resin. These treatments makesit possible to expose an acidic group such as a carboxy group, acarbonyl group, a phenolic hydroxy group, sulfo group or a phosphoricacid on the surface of the surface-treated layer 2.

Chromate Treatment

The surface-treated layer 2 on which an acidic group is exposed can beformed by subjecting the surface of the derivation portion 11 tochromate treatment or phosphoric chromate treatment. A specific exampleof a treatment liquid used in the phosphoric chromate treatment includesan aqueous solution comprising a phenol resin, chromium (III) fluoride,and phosphoric acid. For example, by coating the aqueous solution on thesurface of the derivation portion 11 by an immersion method, a showermethod, a roll coating method or the like, and drying the aqueoussolution, a surface-treated layer on which an acidic group derived fromparticularly a phenol resin or phosphoric acid is exposed can be formed.

Chitosan Treatment

Alternatively, a surface-treated layer 2 including a surface treatingagent containing at least one of chitosans selected from chitosan and achitosan derivative may be provided on the surface of the derivationportion 11.

When this surface treating agent further contains an organic compoundhaving at least one carboxy group in the molecule, the organic compoundpromotes crosslinking of the surface treating agent containingchitosans, which is formed on the surface of the electrode lead wiremember, to improve the strength of a film and corrosion resistance to anelectrolytic solution, so that this is preferable. Examples of such anorganic compound include acetic acid, oxalic acid, malonic acid, malicacid, tartaric acid, mellitic acid, adipic acid, succinic acid, maleicacid, phthalic acid, sebacic acid, citric acid, butanetricarboxylicacid, propanetricarboxylic acid, pyromellitic acid, trimellitic acid,ethylenediaminetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid,diethylenetriaminepentaacetic acid, tannic acid, phytic acid,polyacrylic acid, polymethacrylic acid, and the like. Among them, fromthe viewpoint of crosslinking properties, a tribasic acid, a tetrabasicacid or a pentabasic acid is more preferable.

When this surface treating agent further contains a metal compoundcontaining at least one metal selected from Ti, Zr, Hf, Mo, W, Se, Ce,Fe, Cu, Zn, V, and trivalent Cr, corrosion resistance to an electrolyticsolution is improved, so that this is preferable. These metal compoundsare used in the form of metal oxide, hydroxide, a complex compound, anorganic acid salt, an inorganic acid salt or the like.

Upon formation of the surface-treated layer, chitosans and, ifnecessary, the above-mentioned metal compound and other additives aredissolved in water, and the surface treating agent that has beenprepared into an aqueous solution is coated on the surface of thederivation portion 11, and the surface treating agent is dried.

By thermocompression-bonding the sealing film 1 on the surface of thissurface-treated layer, firm adhesion can be made.

Chitosan that is a main component of this surface treating agent isobtained by deacetylating chitin obtained from shells of crabs, shrimps,and the like. Chitin is ß-poly-N-acetyl-D-glucosamine. Chitosan is apolysaccharide containing an amino group containing2-amino-2-deoxy-D-glucose as a constituent unit. Chitosan forms a saltwith various acids, and when it is dissolved in water, the solutionexhibits cationic property.

Chitosan has high reactivity. The surface treating agent containingchitosans as a main component can adhere to any surface of thederivation portion 11 that is hydrophilic and the sealing film 1 that ishydrophobic.

The chitosans contained in the surface treating agent preferably has aweight average molecular weight in a range of 1,000 to 2,000,000, andmore preferably in a range of 10,000 to 1,000,000. When the molecularweight is smaller than this range, the strength of the film of thesurface-treated layer may not be sufficient. When the molecular weightis larger than this range, the viscosity of an aqueous solution is toohigh, and this solution may cause difficulty in handling.

As the derivative of chitosan, chitosan, a pyrrolidone carboxylic acidsalt of chitosan, hydroxypropylchitosan, glycerylated chitosan,cationized chitosan, a lactic acid salt of chitosan, an adipic acid saltof chitosan, and the like are preferable. The derivative of chitosan mayonly include 2-amino-2-deoxy-D-glucose. Alternatively, the derivativemay be a copolymer of these and other glucose. Furthermore, othersubstituent may be introduced into part of a functional group ofglucosamine.

Method of Performing Treatment with Carboxylic Acid-ModifiedWater-Soluble Resin

Examples of a method of performing treatment with a carboxylicacid-modified water-soluble resin include a method of forming thesurface-treated layer by coating a solution containing a polyvinylalcohol-based resin and a fluorine compound, followed by drying.

The polyvinyl alcohol-based resin is at least one water-soluble resinselected from a polyvinyl alcohol resin and a modified polyvinyl alcoholresin. Usually, the polyvinyl alcohol-based resin has a saponificationdegree of preferably 90 to 100 mol %, and more preferably 95 mol % ormore.

Examples of the polyvinyl alcohol-based resin and a derivative thereofusable in the present invention include an alkyl ether-modifiedpolyvinyl alcohol resin, a carbonyl-modified polyvinyl alcohol resin, anacetoacetyl-modified polyvinyl alcohol resin, an acetamide-modifiedpolyvinyl alcohol resin, an acrylonitrile-modified polyvinyl alcoholresin, a carboxyl-modified polyvinyl alcohol resin, a silicone-modifiedpolyvinyl alcohol resin, an ethylene-modified polyvinyl alcohol resin,and the like. Among them, an alkyl ether-modified polyvinyl alcoholresin, a carbonyl-modified polyvinyl alcohol resin, a carboxyl-modifiedpolyvinyl alcohol resin, and an acetoacetyl-modified polyvinyl alcoholresin are preferable.

Examples of a generally available commercial product of the polyvinylalcohol-based resin include products manufactured by Nippon SyntheticChemical Industry Co., Ltd., JAPAN VAM & POVAL CO., LTD., NIPPON CARBIDEINDUSTRIES CO., INC., and the like. As the polyvinyl alcohol-basedresin, one kind or a mixture of two or more kinds may be used.

<<Sealing Film>>

In the present embodiment, the sealing film 1 is provided in contactwith the surface-treated layer 2.

Substrate Layer

A resin constituting the substrate layer is not particularly limited, aslong as it is a resin having sufficient heat resistance so that it canbe heat-sealed. In the present embodiment, examples thereof include oneor more selected from the group consisting of a fluorine resin,polyether ether ketone, a polyphenylene sulfide resin (SPS),polyphenylene ether, a syndiotactic polystyrene resin, polyethylenenaphthalate, polyethylene terephthalate (PET), a polyimide resin, aphenol resin, an epoxy resin, an acrylic resin, polyketone, a cyclicolefin resin, polymethylpentene, polypropylene, and polyethylene.

In the present embodiment, among the above-mentioned resins, a fluorineresin, PET or SPS is preferable.

Adhesive Agent Composition

In the present embodiment, the adhesive resin layer comprises anadhesive agent composition. The adhesive agent composition used in thepresent embodiment contains imine-modified polyolefin or modifiedpolyolefin having a carbodiimide group.

The adhesive agent composition used in the present embodiment containsimine-modified polyolefin or modified polyolefin having a carbodiimidegroup as an essential component, and may contain optional unmodifiedpolyolefin and an optional olefin-based elastomer.

Imine-Modified Polyolefin

It is preferable that in the present embodiment, imine-modifiedpolyolefin is obtained by graft-treating a polyimine compound having aplurality of imino groups in adhesive polyolefin in the presence of aradical generator. In the present embodiment, imine-modifiedpolypropylene obtained by graft-treating polypropyleneimine ispreferable.

In the present embodiment, a melt flow rate measured under conditions ofa temperature of 190° C. or 230° C. and a load of 2.16 kg in accordancewith ASTM D1238 is preferably 2 g/10 min or more and 25 g/10 min orless, more preferably 2.5 g/10 min or more and 20 g/10 min or less, andfurther preferably 2.8 g/10 min or more and 18 g/10 min or less.

Examples of the adhesive polyolefin include polyethylene, polypropylene,poly-1-butene, polyisobutylene, a copolymer of propylene and ethylene, acopolymer of propylene and an olefin-based monomer, and the like.

Examples of the above-mentioned olefin-based monomer in the case ofcopolymerization include 1-butene, isobutylene, 1-hexene, and the like.

The copolymer may be a block copolymer or a random copolymer.

Inter alia, as the adhesive polyolefin, a polypropylene-based resinpolymerized by using propylene as a raw material, such ashomopolypropylene (propylene homopolymer), a copolymer of propylene andethylene, and a copolymer of propylene and butene, is preferable;particularly, a propylene-1-butene copolymer, that is, a polyolefinresin having a methyl group and an ethyl group on a side chain ispreferable.

Polyimine Compound

In the present embodiment, as the polyimine compound, for example, acompound represented by the following formula (1) is preferable.

[In the formula, R¹, R², and R³ each may be the same or different, andrepresent a non-reactive atom or an organic group, and R¹ and R² may bebonded to each other to form a ring; n is a natural number, and n¹represents an integer of 20 to 2,000.]

R¹, R², and R³ in the formula each may be the same or different, and arepreferably a hydrogen atom, an alkyl group, an alkenyl group, an alkynylgroup, a cycloalkyl group, an aryl group, a heterocycic group or analkoxy group.

As the alkyl group in R¹, R², and R³, an alkyl group having 1 to 10carbon atoms, including a methyl group, an ethyl group, a propyl group,a butyl group, a pentyl group, an isopropyl group, an isobutyl group,and the like is preferable, an alkyl group having 1 to 8 carbon atoms ismore preferable, an alkyl group having 1 to 5 carbon atoms is furtherpreferable, and an alkyl group having 1 to 3 carbon atoms isparticularly preferable.

As the above-mentioned alkenyl group, an alkenyl group having 2 to 10carbon atoms is preferable, an alkenyl group having 2 to 8 carbon atomsis more preferable, an alkenyl group having 2 to 5 carbon atoms isfurther preferable, and an alkenyl group having 2 to 4 carbon atoms isparticularly preferable.

As the above-mentioned alkynyl group, an alkynyl group having 2 to 18carbon atoms, such as an ethynyl group, a 1-propynyl group, and a1-heptynyl group is preferable, an alkynyl group having 2 to 10 carbonatoms is more preferable, an alkynyl group having 2 to 6 carbon atoms isfurther preferable, and an alkynyl group having 2 to 4 carbon atoms isparticularly preferable.

As the above-mentioned cycloalkyl group, a cycloalkyl group having 3 to10 carbon atoms, such as a cyclopropyl group, a cyclobutyl group, acyclopentyl group, a cyclohexyl group, and a cyclooctyl group ispreferable, a cycloalkyl group having 3 to 6 carbon atoms is morepreferable, and a cycloalkyl group having 5 to 6 carbon atoms isparticularly preferable.

As the above-mentioned aryl group, an aryl group having 6 to 10 carbonatoms, such as a phenyl group, a tolyl group, and a naphthyl group ispreferable.

Examples of the above-mentioned heterocyclic group include heterocyclescontaining an oxygen atom as a hetero atom, representatives of which arefused rings such as 5-membered rings including a furan ring, an oxazolering, an isooxazole ring, and a tetrahydrofuran ring; 6-membered ringsincluding a pyran ring; a benzofuran ring, an isobenzofuran ring, adibenzofuran ring, a xanthone ring, a xanthene ring, a chroman ring, anisochroman ring, and a chromene ring; heterocycles containing a sulfuratom as a hetero atom, representatives of which are a thiophene ring, athiazole ring, an isothiazole ring, a thiadiazole ring, a benzothiophenering, and the like; heterocycles containing a nitrogen atom as a heteroatom, representatives of which are fused rings such as 5-membered ringsincluding a pyrrole ring, a pyrazole ring, an imidazole ring, a triazolering, and a pyrrolidine ring; 6-membered rings including a pyridinering, a pyridazine ring, a pyrimidine ring, a pyrazine ring, apiperidine ring, and a morpholine ring; an indole ring, an indolenering, an isoindole ring, an indazole ring, an indoline ring, anisoindoline ring, a quinoline ring, an isoquinoline ring, aquinolinequinoline ring, a quinoxaline ring, a quinazoline ring,phthalazine ring, a purine ring, a carbazole ring, an acridine ring, anaphthoquinoline ring, a phenanthridine ring, a phenanthroline ring, anaphthyridine ring, a benzoquinoline ring, a phenoxazine ring, aphthalocyanine ring, and an anthracyanine ring; and the like.

Examples of the above-mentioned alkoxy group include alkoxy groupshaving 1 to 10 carbon atoms, such as a methoxy group, an ethoxy group, apropoxy group, and an isopropoxy group, and preferably alkoxy groupshaving 1 to 6 carbon atoms.

A suitable specific example of the polyimine compound includespolypropyleneimine.

It is preferable that the polyimine compound has a molecular weight of1,000 or more, but from the viewpoint of reactivity with olefin afteractivation treatment and the like, it is preferable that the polyiminecompound has a higher molecular weight.

Specifically, the molecular weight is preferably 1,000 to 200,000, morepreferably 3,000 to 200,000, and particularly preferably 15,000 to200,000.

Examples of the radical generator used upon graft treatment includeorganic peroxides and organic peresters. Used are benzoyl peroxide,dichlorobenzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(peroxide benzoate)hexyne-3,1,4-bis(tert-butylperoxyisopropyl)benzene, lauroyl peroxide, tert-butylperacetate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, tert-butyl perbenzoate,tert-butyl perphenyl acetate, tert-butyl perisobutyrate, tert-butylper-sec-octoate, tert-butyl perpivalate, cumyl perpivalate, andtert-butyl perdiethylacetate, and other azo compounds, for example,azobisisobutyronitrile and dimethyl azoisobutyrate. Among them, dialkylperoxides such as dicumyl peroxide, di-tert-butyl peroxide,2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3,2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, and1,4-bis(tert-butylperoxyisopropyl)benzene are preferable.

Inter alia, as the radical generator, organic peroxide is preferable. Asthe organic peroxide, an organic peroxide having a half-lifedecomposition temperature of 100° C. or higher is suitable.Specifically, as the organic peroxide, at least one selected from thegroup consisting of dicumyl peroxide, benzoyl peroxide, di-t-butylperoxide, 2,5-dimethyl-di-(t-butylperoxy)hexane,2,5-dimethyl-2,5-(t-butylperoxy)hexyne-3, lauroyl peroxide, and t-butylperoxybenzoate is preferable.

The content of the radical generator is usually 0.001 to 1 part by mass,based on 100 parts by mass of polyolefin.

The above-mentioned imine-modified olefin can be produced by uniformlymixing and treating polyolefin, the polyimine compound, and the radicalgenerator. Specifically, examples of the mixing include a melt kneadingmethod using an extruder, a Banbury mixer, a kneader or the like, asolution method of dissolving the above components in an appropriatesolvent, a slurry method of suspending the above components in anappropriate solvent, a so-called vapor phase graft method, and the like.The above-mentioned treatment temperature is appropriately selected inconsideration of deterioration of polyolefin, decomposition of thepolyimine compound, and the decomposition temperature of the radicalgenerator to be used. For example, in the case of the above-mentionedmelt kneading method, the mixing is usually performed at a temperatureof 60 to 350° C. The above-mentioned treatment temperature is preferably190 to 350° C., and more preferably 200 to 300° C.

Modified Polyolefin Having Carbodiimide Group

It is preferable that the modified polyolefin having a carbodiimidegroup is obtained by reacting polyolefin having a group reactive with acarbodiimide group and a carbodiimide group-containing compound in thepresence of unmodified polyolefin. Examples of the method of thereaction include a method of melt kneading the above components at atemperature of 230° C. or higher.

Examples of the polyolefin include homopolymers or copolymers ofethylene, propylene, 1-butene, 4-methyl-1-pentene, 3-methyl-1-butene,1-hexene, 1-octene, tetracyclododecene, and norbornene.

Examples of the compound having a group reactive with a carbodiimidegroup include unsaturated carboxylic acids such as acrylic acid,methacrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid,itaconic acid, citraconic acid, crotonic acid, isocrotonic acid,norbornenedicarboxylic acid, and bicyclo[2,2,l]hept-2-ene-5,6-dicarboxylic acid, acid anhydrides thereof, andderivatives thereof (for example, acid halide, amide, imide, ester andthe like). Among them, maleic anhydride, (meth)acrylic acid, itaconicanhydride, citraconic anhydride, tetrahydrophthalic anhydride,bicyclo[2,2, l]hept-2-ene-5,6-dicarboxylic anhydride, hydroxyethyl(meth)acrylate, glycidyl methacrylate, and aminopropyl methacrylate arepreferable.

As a method of introducing the compound having a group reactive with acarbodiimide group into polyolefin, the well-known methods can beadopted, and examples thereof include a method of graft-copolymerizingthe compound having a group reactive with a carbodiimide group on apolyolefin main chain, a method of radical-copolymerizing olefin and thecompound having a group reactive with a carbodiimide group, and thelike.

As the polyolefin having a group reactive with a carbodiimide group, amaleic anhydride graft copolymer of crystalline polyolefin, such aspolyethylene, polypropylene, polybutene-1, poly-4-methylpentene-1 or anα-olefin copolymer thereof is preferable, and a maleic anhydride graftcopolymer of polyethylene is more preferable. Particularly, a maleicanhydride graft copolymer of polyethylene having a density of 0.915g/cm³ or more is preferable.

As the carbodiimide group-containing compound, polycarbodiimide having arepetition unit represented by the following formula (2) is preferable.—N═C═N—R⁴—  (2)(In the formula, R⁴ represents a divalent organic group having 2 to 40carbon atoms.)

The polycarbodiimide can be produced by subjecting, in the presence of acondensation catalyst, organic diisocyanate such as aliphaticdiisocyanate, aromatic diisocyanate, or alicyclic diisocyanate to adecarboxylation condensation reaction without a solvent or in an inertsolvent. For example, diisocyanates such as hexamethylene diisocyanate,4,4-diphenylmethane diisocyanate, 1,4-phenylene diisocyanate,2,4-tolylene diisocyanate, xylylene diisocyanate,cyclohexane-1,4-diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, andisophorone diisocyanate can be used.

Examples of the unmodified polyolefin include low density polyethylene,high density polyethylene, linear low density polyethylene,polypropylene, an ethylene-propylene copolymer, an ethylene-α-olefincopolymer, an ethylene-butene copolymer, an ethylene-hexene copolymer,an ethylene-octene copolymer, polybutene-1, poly-4-methyl-1-pentene,poly-3-methyl-1-butene, cyclic polyolefin such as anethylene-tetracyclododecene copolymer, and the like.

Unmodified Polyolefin

In the present embodiment, the adhesive agent composition may containunmodified polyolefin. Examples of the unmodified polyolefin include theunmodified polyolefins described in description of the above-mentionedmodified polyolefin having a carbodiimide group, and inter alia,polypropylene is preferable.

In the present embodiment, the unmodified polyolefin has a melt flowrate measured under conditions of a temperature of 190° C. or 230° C.and a load of 2.16 kg in accordance with ASTM D1238 of preferably 2 g/10min or more and 25 g/10 min or less, more preferably 2.5 g/10 min ormore and 20 g/10 min or less, and further preferably 2.8 g/10 min ormore and 18 g/10 min or less.

In the present embodiment, when the adhesive agent composition containsthe unmodified polyolefin, the amount of the unmodified polyolefin ispreferably 1 part by mass or more and 40 parts by mass or less, and morepreferably 5 parts by mass or more and 35 parts by mass or less, basedon 100 parts by mass of the total amount of the adhesive agentcomposition.

Olefin-Based Elastomer

In the present embodiment, the adhesive agent composition may contain anolefin-based elastomer. Examples of the olefin-based elastomer include ablock copolymer having a hard segment including polystyrene or the likeand a soft segment including polyethylene, polybutadiene, polyisopreneor the like. Examples of the olefin-based polymer usable in theolefin-based elastomer include copolymers of aromatic olefin-aliphaticolefin such as a styrene-butadiene copolymer, a styrene-isoprenecopolymer, and a styrene-ethylene copolymer.

In the present embodiment, when the adhesive agent composition containsthe olefin-based elastomer, the amount of the olefin-based elastomer ispreferably 1 part by mass or more and 40 parts by mass or less, and morepreferably 5 parts by mass or more and 35 parts by mass or less, basedon 100 parts by mass of the total amount of the adhesive agentcomposition.

<<Laminate for Battery Outer Package>>

Examples of the laminate 20 for a battery outer package to which theelectrode lead wire member 10 of the present embodiment is fused includea laminated film in which the sealant layer 22 is laminated on onesurface of the metal foil layer 21 and the film substrate layer 23 islaminated on the other surface of the metal foil layer 21, as shown inFIG. 1, and the like. The laminate 20 for a battery outer package mayinclude another layer to be laminated.

The laminate 20 for a battery outer package is molded into a drawncontainer.

Examples of the metal foil layer 21 include an aluminum foil, astainless foil, a copper foil, an iron foil, and the like. The metalfoil layer 21 may be subjected to surface treatment such as chemicalconversion treatment.

As the resin forming the sealant layer 22 of the laminate 20 for abattery outer package, a resin which can be fused with the sealing film1 is selected. Examples of such a resin include a polypropylene-basedresin, and a homopolymer of polypropylene, a copolymer of propylene andethylene, and the like can be used for the polypropylene-based resin.

When the sealant layer 22 is a polyethylene-based resin, low densitypolyethylene, linear low density polyethylene, and the like can be used.

The resin constituting the film substrate layer 23 is not particularlylimited, but polyamide, polyethylene terephthalate (PET), a phenolresin, polypropylene, and the like, which have large strength, aresuitably used.

EXAMPLES

The present invention will be described in further detail below by wayof examples, but the present invention is not limited by these examples.

<Production of Modified Polyolefin (A)-3 Having Carbodiimide Group>

To 25 parts by weight of maleic acid-modified polypropylene were added25 parts by weight of polypropylene manufactured by Mitsui Chemicals,Inc. and 3 parts by weight of polycarbodiimide (manufactured byNisshinbo Holdings Inc., product name CARBODILITE HMV-8CA), thematerials were melted and kneaded with a 65 mm φ single screw extruder(manufactured by Modern Machinery Ltd.) at 250° C. (retention time=2minutes) to obtain a modified polyolefin (A)-3 having a carbodiimidegroup.

<Production of Adhesive Agent Composition>

An adhesive polyolefin resin, an olefin-based elastomer, and unmodifiedpolyolefin shown in the following Table 1 were melted and kneaded at280° C. for 2 minutes to produce adhesive agent compositions 1 to 6.

TABLE 1 Adhesive polyolefin Olefin-based Unmodified resin elastomerpolyolefin Adhesive agent (A)-1 — — composition 1 [100] Adhesive agent(A)-2 (A1)-1 — composition 2 [70] [30] Adhesive agent (A)-1 — (B)composition 3 [70] [30] Adhesive agent (A)-1 (A1)-1 (B) composition 4[70] [15] [15] Adhesive agent (A)-3 — — composition 5 [100] Adhesiveagent (A)-4 — — composition 6 [100]

In the above-mentioned Table 1, respective symbols mean the followingmaterials.

A numerical value in the parenthesis is an addition amount (parts bymass).

(A)-1: Imine-modified polyolefin (manufactured by Mitsui Chemicals,Inc., ADMER IP, melt flow rate: 3).

(A)-2: Imine-modified polyolefin (manufactured by Mitsui Chemicals,Inc., ADMER IP, melt flow rate: 15).

(A)-3: Modified polyolefin having a carbodiimide group.

(A)-4: Acid-modified polyolefin (manufactured by Mitsui Chemicals, Inc.,product name: ADMER).

(A1)-1: Olefin-based elastomer resin (MP: 120° C.).

(B): Polypropylene resin manufactured by SunAllomer Ltd. (melt flowrate: 3)

As an adhesive laminate A, a laminate was produced in which the adhesiveagent composition 1, a PET film as a substrate layer, and the adhesiveagent composition 1 are laminated in that order.

<Production of Electrode Lead Wire Member>

<<Step of Surface-Treating Electrode Lead Wire Member>>

As a derivation sealing portion of an electrode lead wire member for alithium battery, an aluminum piece obtained by cutting an aluminum platehaving a thickness of 200 μm into the dimension of width 50 mm×length 60mm was used. An aqueous solution obtained by dissolving 1% by mass of anamorphous polymer having a skeleton of polyvinyl alcohol containing ahydroxy group (manufactured by Nippon Synthetic Chemical Industry Co.,Ltd., product name: G Polymer Resin) and 1% by mass of chromium (III)fluoride was applied onto both surfaces of the defatted and washedaluminum piece with a dispenser so that the thickness after drying underheat was 1 μm, to laminate a surface-treated layer (thin film coatinglayer) (Treatment 1). Further, the laminate was dried under heat in anoven at 200° C., and the resin was baked and simultaneously crosslinkedto obtain an electrode lead wire member.

<<Step of Producing Sealing Film>>

Each of the adhesive agent compositions 1 to 6 was prepared into a 100μm sealing film by melt casting.

<<Step of Sealing Sealing Film and Laminate for Battery Outer Package onSurface-Treated Electrode>>

A sealing film having a width 50 mm×a length 20 mm was joined on thesurface-treated layer (thin film coating layer) of the derivationsealing portion of the electrode lead wire member by heat sealing.Further, a laminate for a battery outer package having a width 50 mm×alength 60 mm and having a thickness of 145 μm, which included analuminum foil (thickness 40 μm)/polypropylene film (thickness 80 μm),was heat-sealed on the sealing film, to prepare a part of a batteryaccommodating container.

<<Method of Measuring Adhesive Strength Between Electrode Lead WireMember and Sealing Film>>

Method of measuring adhesive strength between derivation sealing portionof electrode lead wire member and sealing film: the strength wasmeasured by the measuring method defined in JIS C6471 “Test Methods ofCopper-Clad Laminates for Flexible Printed Wiring Boards”.

In the measuring method, the electrode lead wire member was fixed, andthe laminate for a battery outer package was peeled under the followingconditions.

Peeling Conditions

180° peeling

Peeling rate: 300 mm/min

For the adhesive strength, the values obtained by the measurement wereassessed based on the following criteria, and the results thereof aredescribed in Table 2.

Adhesive Strength

50 N/inch or more: ⊙

45 N/inch or more and less than 50 N/inch: ◯

40 N/inch or more and less than 45 N/inch: Δ

35 N/inch or more and less than 40 N/inch: x

<<Test of Resistance to Electrolytic Solution>>

As a test of resistance to an electrolytic solution, an electrolyticsolution strength retention rate was measured by the following method.

Method of measuring electrolytic solution strength retention rate: thelaminate for a battery outer package was prepared into a four-sided bagof 50×50 mm (heat sealing width: 5 mm), 0.5% by mass of pure water wasadded to a PC/DEC electrolytic solution with 1 mol/liter LiPF₆ addedthereto, and 2 cc of the resulting solution was weighed, filled therein,and packaged. A sample for measurement was placed into this four-sidedbag, the bag was stored in an oven at 60° C. for 100 hours, andthereafter, the interlayer adhesive strength (k2) between the electrodelead wire member and the sealing film was measured.

Herein, a ratio between the interlayer adhesive strength (k1) betweenthe electrode lead wire member and the sealing film before exposure tothe electrolytic solution, which had been measured in advance, and theinterlayer adhesive strength (k2) after exposure to the electrolyticsolution was defined as electrolytic solution strength retention rateK=(k2/k1)×100(%).

The values obtained by the measurement were assessed based on thefollowing criteria, and the results thereof are described in Table 2.

Electrolytic Solution Strength Retention Rate K

K=90% or more: └

K=85% or more and less than 90%: ◯

K=80% or more and less than 85%: Δ

K=75% or more and less than 80%: x

TABLE 2 Assessment Test of resistance to Electrode Surface-treatedAdhesive electrolytic material Adhesive layer layer strength solutionExample 1-1 Aluminum Adhesive agent Treatment 1 ⊙ ◯ plate composition 1Example 1-2 Aluminum Adhesive agent Treatment 1 ◯ ⊙ plate composition 2Example 1-3 Aluminum Adhesive agent Treatment 1 ◯ ◯ plate composition 3Example 1-4 Aluminum Adhesive agent Treatment 1 ◯ Δ plate composition 4Example 1-5 Aluminum Adhesive agent Treatment 1 ◯ ◯ plate composition 5Example 1-6 Aluminum Adhesive laminate A Treatment 1 ⊙ ◯ plate Example2-1 Ni plated Adhesive agent Treatment 1 ⊙ ◯ copper plate composition 1Example 2-2 Ni plated Adhesive agent Treatment 1 ◯ ⊙ copper platecomposition 2 Example 2-3 Ni plated Adhesive agent Treatment 1 ◯ ◯copper plate composition 3 Example 2-4 Ni plated Adhesive agentTreatment 1 ◯ Δ copper plate composition 4 Example 2-5 Ni platedAdhesive agent Treatment 1 ◯ ◯ copper plate composition 5 Example 2-6 Niplated Adhesive laminate A Treatment 1 ⊙ ◯ copper plate ComparativeAluminum Adhesive agent Treatment 1 Δ X Example 1 plate composition 6Comparative Ni plated Adhesive agent Treatment 1 Δ X Example 2 copperplate composition 6

As shown in the above-mentioned results, in Examples 1-1 to 1-6 to whichthe present invention was applied, an adhesive force to an aluminumplate was high and resistance to an electrolytic solution was also high,as compared with Comparative Example 1.

Furthermore, in Examples 2-1 to 2-6 to which the present invention wasapplied, an adhesive force to a Ni plated copper plate was high andresistance to an electrolytic solution was also high, as compared withComparative Example 2.

DESCRIPTION OF THE REFERENCE NUMERALS

-   1: Sealing film-   2: Surface-treated layer-   10: Electrode lead wire member-   11: Derivation portion-   17: Lithium ion battery-   19: Side edge-   20: Laminate for battery outer package-   20 a: Battery-   21: Metal foil layer-   22: Sealant layer-   23: Film substrate layer

What is claimed is:
 1. An electrode lead wire member comprising: aderivation portion extending in one direction; a surface-treated layerformed, at said derivation portion, on a surface of said derivationportion; and a sealing film provided in contact with saidsurface-treated layer, wherein said sealing film has an adhesive resinlayer in contact with said surface-treated layer, said adhesive resinlayer contains imine-modified polyolefin, and said surface-treated layerhas an acidic group.
 2. The electrode lead wire member according toclaim 1, wherein said sealing film only includes said adhesive resinlayer.
 3. The electrode lead wire member according to claim 1, whereinin said sealing film, said adhesive resin layer, a substrate layer, anda second adhesive resin layer are laminated in that order.
 4. Theelectrode lead wire member according to claim 3, wherein a resinconstituting said substrate layer is one or more selected from the groupconsisting of a fluorine resin, polyether ether ketone, a polyphenylenesulfide resin, polyphenylene ether, a syndiotactic polystyrene resin,polyethylene naphthalate, polyethylene terephthalate, a polyimide resin,a phenol resin, an epoxy resin, an acrylic resin, polyketone, a cyclicolefin resin, polymethylpentene, polypropylene, and polyethylene.
 5. Theelectrode lead wire member according to claim 1, comprising one pair ofsealing films holding said derivation portion, wherein in said one pairof said sealing films, adhesive resin layers face and come in contactwith each other, and simultaneously come in contact with a wholecircumference in a circumferential direction of said derivation portionto cover said derivation portion.
 6. A battery comprising the electrodelead wire member with the sealing film according to claim 1.